Begonia magentifolia Kiew & S.Julia

Sang, Julia, Kiew, Ruth & Yiing, Ling Chea, 2018, The Begonia flora of Gunung Mulu and Gunung Buda National Parks, Sarawak, Borneo, including five new species, Phytotaxa 381 (1), pp. 58-79 : 69

11. Begonia magentifolia Kiew & S.Julia ( Figure 7 )

Phytotaxa 99(1) (2013) 17; Kiew et al., Guide to Begonias of Borneo (2015) 176. Type: — MALAYSIA. Borneo. Sarawak. Marudi District: Gunung Mulu NP, boardwalk to Clearwater Water Cave , 4 Oct 2007, Julia et al. S 99215 (holotype SAR!) .

Small, unbranched erect herb. Stems wiry, green, 10–50 cm long, 3–6 mm diam. when dry; internodes 0.5–1.5 cm long in the upper stem and to 2.5–4 cm near the base of the stem; flowering at 9 cm tall. Stem, stipules and petioles densely covered in long brown bristles ca. 5 mm long. Stipules magenta or pale green, narrowly lanceolate, 8–15 × 2.5–6 mm, midrib thick, margin entire, apex acuminate, seta 1.5–4 mm long, persistent. Leaves alternate, distant. Petiole brownish, (4–) 7–17 mm long, 1.5–2 mm diam., terete. Lamina not oblique (petiole does not form an angle with the midrib), dark jade green above, reddish magenta below, sometimes green on both surfaces and then paler beneath, hairy on both surfaces, scattered hairs uniseriate, 1–3 mm long, frequent above, less dense beneath, papery when dry, unequally lanceolate to narrowly obovate, (9.5–)10–16.5 × (2.5–) 3.7–4.5 cm, slightly asymmetric, broad side 1.5–2.5 cm, base unequal, rounded, basal lobes 2–5 mm, margin ciliate and minutely serrate, apex acute to slightly acuminate; venation pinnate with 3–6 veins on either side of the midrib, impressed above when fresh, when dry prominent above, secondary and tertiary veins prominent beneath. Inflorescences protogynous, axillary with one flower per axil, female flowers produced on the lower part of the stem. Bracts ovate, ca. 3 × 1 mm, margin entire, caducous; bracteoles magenta, lanceolate, ca. 2 × 0.5 mm. Male flower: pedicel 8–12 mm long; tepals 2, white or palest pink, broadly oval, 6–12 × 7–12 mm, sprinkled with hispid red hairs outside, glabrous inside, margin entire, apex rounded; stamens 23–25, cluster ca. 3 mm across, globose, stalked to 1 mm long; filament ca. 2 mm long; anthers yellow, oblong, ca. 0.5 × 0.1 mm, apex emarginate. Female flower single, sessile; ovary yellowish or scarlet, globose, 8–13 × 8–13 mm; beak to 1.5 mm long, wings 3, ca. 2 mm wide, equal; locules 3, placentas 2 per locule; tepals 5, isomorphic, sparsely hispid all over, pink, elliptic, 2–5.5 × 2–4 mm, margin entire, apex rounded; styles 3, 2 mm long, free to base and bifurcating with the ultimate branches broadly U-shaped; stigma anchor-shaped, 2 mm long, papillose, forming a continuous twisted band. Fruits yellowish, 8–9 mm long, 9–13 mm wide across the wings, wings 3, well-developed, 4.5–5 mm wide, another 3 wings smaller or not well-developed; beak 1–2 mm long, stigma persistent. Seeds barrel-shaped, 0.2–0.3 × 0.1 mm, collar cells half the length of the seed.

Distribution: — MALAYSIA. Borneo. Endemic in Sarawak. Recorded from Marudi District (Gunung Mulu NP & Tama Abu Permanent Forest). In Gunung Mulu NP, the species is widespread and common particularly along the trail to Camp 5.

Habitat: —In lowland forest on sandy soil or on limestone-derived soil at elevations to 140– 360 m.

Additional specimens examined: — MALAYSIA. Borneo. Sarawak. Marudi District: Gunung Mulu NP – Sungai Melinau Paku, Stone 136 28 (SAR); Gunung Mulu, Burtt & Woods B 2070 (E, SAR); Ulu Sungai Berar, Anderson S 39363 (L, SAR); Sungai Berar, Kiew RK 485 (KEP), RK 493 (KEP), Lewis 310 (SAR); Gua Rusa, Argent & Kerby 813 (E, SAR); Camp 1, Ling et al. SFC 6932 (SAR), Sungai Ripan, along the trail from Paku Waterfall to Camp 1, Julia et al. SFC 6670 (SAR), Camp 1, tributary of Sungai Ripan, Julia et al SFC 6672 (SAR), trail from Kuala Litut to Camp 5, Julia et al. SFC 6678 (SAR), Sungai Lansat (tributary of Sungai Tutoh), Julia et al. SFC 6801 (SAR); Tama Abu Permanent Forest – Sungai Baleh, Julia et al. SFC 8101 (SAR), SFC 8126 (SAR), Ling et al. SFC 8494 (SAR), SFC 8416 (SAR).

Notes: —A more detailed description is provided together with a figure to show the flowers because more individuals were encountered during the present survey. Two colour forms were observed; one with leaves green above and pale green below; the other bronzy green above and magenta below. In addition, fruit is commonly found with three well-developed wings and three small wings. This is unusual in Bornean Begonia that usually have three wings but it is known from a very few species such as B. hexaptera Sands (1997: 434) from Brunei.

Figures

FIGURE 7. Begonia magentifolia Kiew & S.Julia. A Habit; B. Stipule and stem; C. Inflorescence along the stem; D & E. Male flower; F & G. Female flower; H. Fruit; I. Transverse section of fruit. Photos A–C from SFC 6678 by S. Julia and photos D–I from SFC 6932 by C.Y. Ling.